A key fob is a remote control assembly for signaling a receiver located on a vehicle. The key fob includes a housing having at least one flexible dome that is depressable for transmitting a signal. Typically, three or four domes protrude through the housing, each for signaling a different electrical component on the vehicle, such as, for example a door lock, a trunk latch, a panic alert, and the like. Each of the domes is depressable independent of the other domes for initiating transmission of the signal.
A circuit board is disposed within the housing. An electrical circuit is printed on the circuit board for generating the signals. The electrical circuit includes a switch situated beneath each of the domes. Typically, each switch is closed by depressing the adjacent dome. The dome includes conductive material that contacts the switch allowing current to flow through the circuit to a transmitter.
Circuit boards now being used in key fobs are formed from a rigid composite material having a thickness of up to two millimeters. Consumer trends have indicated fob is by reducing the thickness of the circuit board the electrical circuit is printed on. However, to do so, provisions must be made for the switch to meet the operational standards required of the prior art. Thus, a need exists for a thinner circuit board that still provides each of the features available in switches used in today""s circuit boards.
The present invention discloses a flexible switch disposed upon a flexible circuit board. A key fob assembly for signaling a receiver on a vehicle includes a housing having at least one depressable dome for initiating transmission of a signal. A circuit board is disposed within the housing. An electrical circuit is printed on the circuit board. The electrical circuit includes a switch situated beneath the dome. The circuit board is formed from a flexible composite material having a thickness of less than one millimeter. A bulge is molded into the circuit board having the switch is printed beneath. The bulge is depressable for closing the switch and transmitting the signal. The assembly includes conductive material adjacent the switch for closing the switch when the bulge is depressed by the dome.
Combining the flexible circuit with the depressable bulge for closing the switch provides the ability to reduce the overall thickness of the key fob. First, the flexible circuit board is thinner than the conventional rigid circuit boards therefore requiring less volume displaced within the housing. Further, the flexible circuit board does not require a fixed linear space in the housing as a rigid circuit board does. The flexible circuit board can be manipulated to fit irregular contours in a smaller housing. Still further, the depressable bulge meets operational features available in the prior art switches commonly used in the thicker circuit boards of current key fobs.